View Full Version : skinny tire stability
11-22-2006, 11:28 PM
Hi, I just discovered this site and am very impressed with it. Its time to replace the tires on my 04 unlimited. I like the ideas about improved off-road performance of skinny tires.(from the articles on-site) I am concerned about the lateral stability of a 33x10.50 vs. 33x12.50 on-road. Any words of advice from those experienced with pizza-cutters? I have 2" lift and 15x8 wheels w/ 5.5" backspacing. I like 32x11.50s and 33x12.50s, but really don't want to use wheel spacers or get new wheels. Hence interest in 10.50s. Thank in advance, this seems like the right site for advice.
11-23-2006, 12:28 AM
I run 33x9.50-15 BFG AT/KO on 7" wheel with 6" rear spacing. I have added 1.25" spacers to the front and 3" spacers to the rear, as well as poly bushings for the swaybar and good shocks.
Lateral stability feels good. I do not push limits, so I can not attest to what they may be.
It is comfortable for me. Expedition loaded I am at 5900 lbs. Aired down, a cargo box on the top and swaybar disconnected it handles pretty good. I don't think it would be competitive in a slalom race.
Tires aired up, swaybar connected and "empty" It handles pretty good.
In my case I would say it handles as good as stock despite the size of the tires. The addition of poly bushings, good shocks, rear springs and wider track equaled the perceived loss the taller sidewalls may have given.
In my case performance was enhanced. The "pizza cutters" were lighter than the 31x10.5-15 tires I had been using. The reduced mass make them "snappy". It takes less horsepower to get them going. The height matched the lower gear ratio I have better. The reduced rolling resistance may have been a contributing factor to slightly improved fuel mileage too.
The narrower, lighter tire may reduce the stress on the front steering components, as well as suspension components. I know offroad they float over the terrain very nicely.
With the tread width matching the rim width I can run higher air pressures on the street and not wear out the center of the tread. That helps reduce rolling resistance and hopefully improve mileage.
I would match the tread to the wheel and go with the 33x10.5-15, unless you do slalom race, and then perhaps some taller wheels would be a good choice? ;)
11-23-2006, 04:04 AM
Are you asking about on road stability or off road?
Off-Road stability is more a function of track width and tread design then tread width. A narrower tire typically allows a lower lift height, which provides stable and predictable handling.
Suspension design and shock performance has much to do with stability as well.
I drive my truck pretty fast on and off road and am pleased with the grip, which IMHO is mostly related to suspension.
On road, a wider tire will provide better lateral grip due to less tire lift (and the reason why performance tires are wide, along with adhesion).
Oh, and welcome to the site :)
11-23-2006, 07:53 PM
I used to run 33x9.50's on my FJ80 then switched to 33x12.50's. I had always run skinny tires and this was my first more typical width offroad tire i had run. Yes, the 9.50's had a bit more noticeable sidewall flex that contributed a bit to lean in hard corners on pavement. It wasn't bad though and by no means did I find it bad enough to be annoyed. The 9.50's did great in soupy mud, loose snow (provided it wasn't deeper then my clearance), and packed snow. The only place I feel like I have more traction and ability with my 12.50's is on soft sand and when I'm aired down, on rock I get more smear and thus traction. On the road they are louder and contribute noticeably to rolling resistance and thus mileage. My next set (or possibly a second set) of tires will be 33x10.50 which I think will be the best balance for my uses.
11-23-2006, 11:43 PM
I used to run 33x9.50x15s until they stopped making them. I now run 33x10.50. Stability???? Never noticed any problems running a 300+HP supercharged Jeep hard, towing a trailer in the nasty stuff nor the hwy...nuf said
11-24-2006, 01:18 PM
Thanks for everyone's input. Sounds like great real-world experience. Scott-My questions were regarding off-road, but also safety on-road with the Wrangler's narrow axle-width. Thank you for following up. Also, any thoughts on MPG differences between 33x10.50 and 32.11.50? My motor is the 4.0 I6, I have 3.73 gearing. Will the 32's be significantly better for gas milage? Thanks all.
Powered by vBulletin® Version 4.1.11 Copyright © 2013 vBulletin Solutions, Inc. All rights reserved.